US5250633AExpiredUtilityPatentIndex 92

Fibers and fibrets from blends of polybezimidazoles and aromatic polyamides, aromatic polyamide-hydrazides or aromatic polyamides containing heterocyclic linkages

Assignee: HOECHST CELANESE CORPPriority: Jan 29, 1991Filed: Jan 29, 1991Granted: Oct 5, 1993

Est. expiryJan 29, 2011(expired)· nominal 20-yr term from priority

Inventors:CALUNDANN GORDON W CHENEVEY EDWARD C CHUNG TAI-SHUNG

C08L 79/04D01F 6/905C08L 77/00D01D 5/40C08L 79/02

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Claims

Abstract

Fibers and fibrets of a novel miscible blend of component polymers comprising from about 5 weight percent to about 95 weight percent of a polybenzimidazole and from about 95 weight percent to about 5 weight percent of an aromatic polyamide, aromatic polyamide-hydrazide or aromatic polyamide containing heterocyclic linkages. Miscibility of the component polymers of the blend is indicated by infrared, X-Ray and Differential Scanning Calorimetry analyses and electron photomicrographs. In fibers or fibrets of a blend mostly comprised of a polybenzimidazole, it is preferred that the aromatic polyamide, aromatic polyamide-hydrazide or aromatic polyamide containing heterocyclic linkages be present in the blend in an amount sufficient to yield a blend with improved tensile properties compared to the polybenzimidazole and more thermally processable than the polybenzimidazole. The fibers or fibrets of the blend have a lower moisture regain than polybenzimidazole fibers or fibrets. In fibers or fibrets of a blend mostly comprised of an aromatic polyamide, aromatic polyamide-hydrazide or aromatic polyamide containing heterocyclic linkages, it is preferred that the polybenzimidazole be present in the blend in an amount sufficient to yield a blend with increased thermal stability and nonflammability compared to the aromatic polyamide, aromatic polyamide-hydrazide or aromatic polyamide containing heterocyclic linkages. The fibers or fibrets may be post-treated with heat or sulfuric acid in order to minimize their shrinkage when they are subsequently subjected to heat and in order to increase their resistance to solvents and acid.

Claims

exact text as granted — not AI-modified

What is claimed is: 
     
       1. Fibers or fibrets comprised of a blend of component polymers comprising from about 5 weight percent to about 95 weight percent of a polybenzimidazole and from about 95 weight percent to about 5 weight percent of an aromatic polyamide. 
     
     
       2. Fibers or fibrets as claimed in claim 1 in which the polybenzimidazole contains units of the formula: ##STR18## wherein &gt;Ar 1  &lt; represents a tetravalent aromatic moiety having the formula: ##STR19## wherein R 1  is --O--, --SO 2  --, --CH═CH--, or (--CH 2  --) x  and x is an integer of from 1 to 4; and --Ar 2  -- represents a divalent aromatic moiety having the formula: ##STR20## wherein R 2  is --O--, --SO 2  --, --CH═CH--, or (--CH 2  --) x  and x is an integer of from 1 to 4. 
     
     
       3. Fibers or fibrets as claimed din claim 2 in which the polybenzimidazole is poly-2,2&#39;-(m-phenylene)-5,5&#39;-bibenzimidazole. 
     
     
       4. Fibers or fibrets as claimed in claim 1 in which the aromatic polyamide contains units of the formula: ##STR21## wherein Ar 3  and Ar 4  and Ar 5  represent divalent aromatic moieties having from 6 to about 18 carbon atoms or mixtures thereof; and wherein b is 0 or a value less than 0.5, and the sum of a and b is equal to 1. 
     
     
       5. Fibers or fibrets as claimed in claim 4 in which the aromatic polyamide is comprised of units ##STR22## where, unit B is not identical to unit C or unit D; R 3  is a halogen radical, or an alkyl or alkoxy radical each having up to 4 carbon atoms; R 4  is a methylene radical or a grouping --O--Ar 3  --O, wherein --Ar 3  -- is as specified above, and the mole % proportions of the diamine components B, C and D relative to the total amount of diamine components are within a domain which is defined by the following corner points: point Q corresponds to 5 mole % of B, 45 mole % of C and 50 mole % of D;   point R corresponds to 45 mole % of B, 5 mole % of C and 50 mole % of D;   point S corresponds to 60 mole % of B, 35 mole % of C and 5 mole % of D;   point T corresponds to 20 mole % of B, 75 mole % of C and 5 mole % of D;   point U corresponds to 5 mole % of B, 80 mole % of C and 15 mole % of D;   and the aromatic polyamide has an inherent viscosity of about 2.4 to 6.5 dl/g (measured on solutions of 0.5 g of polyamide in 100 ml of 98% by weight concentrated H 2  SO 4  at 25° C.).   
     
     
       6. Fibers or fibrets as claimed in claim 5 in which the proportions of diamine components B, C and D relative to the total amount to diamine components are within a domain which is defined by the following corner points: point Q&#39; corresponds to 15 mole % of B, 45 mole % of C and 40 mole % of D;   point R&#39; corresponds to 40 mole % of B, 20 mole % of C and 40 mole % of D;   point S&#39; corresponds to 50 mole % of B, 40 mole % of C and 10 mole % of D;   point T&#39; corresponds to 15 mole T of B, 75 mole % of C and 10 mole % of D.   
     
     
       7. Fibers or fibrets as claimed in claim 5 in which the proportions of diamine components B, C and D relative to the total amount of diamine components are within a domain which is defined by the following corner points: point W corresponds to 5 mole % of B, 45 mole % of C and 50 mole % of D;   point X corresponds to 45 mole % of B, 5 mole % of C and 50 mole % of D;   point Y corresponds to 45 mole % of B, 40 mole T of C and 15 mole % of D;   point Z corresponds to 5 mole % of B, 80 mole % of C and 15 mole % of D;   and the aromatic polyamide has an inherent viscosity of about 2.4 to 5.0 dl/g (measured on solutions of 0.5 g of polyamide in 100 ml of 98% by weight concentrated H 2  SO 4  at 25° C.).   
     
     
       8. Fibers or fibrets as claimed in claim 7 in which the proportions of diamine components B, C and D relative to the total amount of diamine components are within a domain which is defined by the following corner points: point W&#39; corresponds to 15 mole % of B, 50 mole % of C and 35 mole % of D;   point X&#39; corresponds to 45 mole % of B, 20 mole % of C and 35 mole % of D;   point Y corresponds to 45 mole % of B, 40 mole % of C and 15 mole % of D;   point Z&#39; corresponds to 15 mole % of B, 70 mole T of C and 15 mole % of D.   
     
     
       9. Fibers or fibrets as claimed in claim 5 in which Ar 3  and Ar 4  each denote a 1,4-phenylene radical; R.sup. is --CH 3 , --OCH 3  or --Cl; and R 4  is a ##STR23## 
     
     
       10. Fibers or fibrets as claimed in claim 5 in which the aromatic polyamide has repeating units derived from terephthalic acid and the following diamines: ##STR24## 
     
     
       11. Fibers or fibrets as claimed in claim 10 in which the mole ratio of (i):(ii):(iii) is 50:25:25 or 37.5:37.5:25. 
     
     
       12. Fibers or fibrets as claimed in claim 1 wherein said polyamide comprises an aromatic polyamide-hydrazide or an aromatic polyamide containing heterocyclic linkages. 
     
     
       13. Fibers or fibrets as claimed in claim 12 in which the aromatic polyamide-hydrazide has the following unit formula: ##STR25## wherein Ar 5 , Ar 7 , Ar 8  and Ar 9  represent divalent aromatic moieties having from 6 to about 18 carbon atoms or mixtures thereof; and wherein d has a value of 0.5 to 1, e is 0 or a value less than 0.5, g is 0 or a value less than 0.5, and the sum of d, e and g is equal to f. 
     
     
       14. Fibers or fibrets as claimed in claim 13 in which the polyamide-hydrazide is prepared from terephthaloyl chloride and para-amino benzhydrazide. 
     
     
       15. Fibers or fibrets as claimed in claim 12 in which the aromatic polyamide containing heterocyclic linkages has the following unit formula: R1 ? ##STR26## wherein Y&#39; and Y separately represent Ar 10  and Ar 10  --X--Ar 11  --X--Ar 10 , wherein Ar 10  and Ar 11  are multivalent aromatic moieties having from 6 to about 18 carbon atoms, or mixtures thereof; and X is a 5 or 6 member ring heterocyclic radical containing 2 or 3 hetero ring elements selected from the group consisting of N, O and S, and wherein at least one Ar 10  --X--Ar 1  --X--Ar 10  radical must be present in the recurring structural unit and the moiety 13 X--Ar 11  --X-- may represent a fused ring system. 
     
     
       16. Fibers or fibrets as claimed in claim 15 in which all occurrences of X in the aromatic polyamide containing heterocyclic linkages are the same and the aromatic polyamide containing heterocyclic linkages has at least one plane of symmetry in each recurring unit. 
     
     
       17. Fibers or fibrets as claimed in claim 15 in which the aromatic polyamide containing heterocyclic linkages is prepared from ##STR27## and 4,4&#39;-diaminodiphenyl ether. 
     
     
       18. Fibers or fibrets as claimed in claim 1 in which the aromatic polyamide contains a phthalate moiety, ##STR28## which is comprised of moieties from isophthalic acid, terephthalic acid or a mixture of isophthalic acid and terephthalic acid moieties in a ratio ranging from 99% isophthalic acid to 1% terephthalic acid moieties and 1% isophthalic acid to 99% terephthalic acid moieties. 
     
     
       19. Fibers or fibrets as claimed in claim 1 in which the polybenzimidazole contains units of the formula: ##STR29## wherein &gt;Ar 1  &lt; represents a tetravalent aromatic moiety having the formula: ##STR30## wherein R 1  is --O--, --SO 2  --, --CH═CH--, or (--CH 2  --) x  and x is an integer of from 1 to 4; and --Ar 2  -- represents a divalent aromatic moiety having the formula: ##STR31## wherein R 2  is --O--, --SO 2  --, --CH═CH--, or (--CH 2  --) x  and x is an integer of from 1 to 4; and the aromatic polyamide contains units of the formula: ##STR32## wherein Ar 3  and Ar 4  and Ar 5  represent divalent aromatic moieties having from 6 to about 18 carbon atoms or mixtures thereof; and wherein b is 0 or a value less than 0.5, and the sum of a and b is equal to 1. 
     
     
       20. Fibers or fibrets as claimed in claim 19 in which the polybenzimidazole is poly-2,2&#39;-(m-phenylene)-5,5&#39;-bibenzimidazole and the aromatic polyamide has repeating units derived from terephthalic acid and the following diamines: ##STR33## in a mole ratio of 50:25:25 or 37.5:37.5:25. 
     
     
       21. Fibers or fibrets as claimed in claim 12 in which the polybenzimidazole contains units of the formula: ##STR34## wherein &gt;Ar 1  &lt; represents a tetravalent aromatic moiety having the formula: ##STR35## wherein R 1  is --O--, --SO 2  --, --═CH--, or (--CH 2  --) x  and x is an integer of from 1 to 4; and --Ar 2  -- represents a divalent aromatic moiety having the formula: ##STR36## wherein R 2  is --O--, --SO 2  --, --CH═CH--, or (--CH 2  --) x  and is an integer of from 1 to 4; and the aromatic polyamide-hydrazide has the following unit formula: ##STR37## wherein Ar 6 , Ar 7 , Ar 8  and Ar 9  represent divalent aromatic moieties having from 6 to about 18 carbon atoms or mixtures thereof; and wherein d has a value of 0.5 to 1, e is 0 or a value less than 0.5, g is 0 or a value less than 0.5, and the sum of d, e and g is equal to f. 
     
     
       22. Fibers or fibrets as claimed in claim 12 in which the polybenzimidazole contains units of the formula: ##STR38## wherein &gt;Ar 1  &lt; represents a tetravalent aromatic moiety having the formula: ##STR39## wherein R 1  is --O--, --SO 2  --, --CH═CH--, or (--CH 2  --) x  and x is an integer of from 1 to 4; and --Ar 2  -- represents a divalent aromatic moiety having the formula: ##STR40## wherein R 2  is --O--, --SO 2  --, --CH═CH--, or (--CH 2  --) x  and x is an integer of from 1 to 4; and the aromatic polyamide containing heterocyclic linkages has the following unit formula: ##STR41## wherein Y&#39; and Y separately represent Ar 10  and Ar 10  --X--Ar 11  --X--Ar 10 , wherein Ar 10  and Ar 11  are multivalent aromatic moieties having from 6 to about 18 carbon atoms, or mixtures thereof; and X is a 5 or 6 member ring heterocyclic radical containing 2 or 3 hetero ring elements selected from the group consisting of N, O and S, and wherein at least one Ar 10  --X--Ar 11  --S--Ar 10  radical must be present in the recurring structural unit and the moiety --C--Ar 11  --X-- may represent a fused ring system. 
     
     
       23. Fibers or fibrets as claimed in claim 22 in which all occurrences of X in the aromatic polyamide containing heterocyclic linkages are the same and the aromatic polyamide containing heterocyclic linkages has at least one plane of symmetry in each recurring unit. 
     
     
       24. Fibers or fibrets as claimed in claim 1 which are comprised of a major amount of a polybenzimidazole and the aromatic polyamide is present in the fibers or fibrets in a minor amount sufficient to yield fibers or fibrets with greater tensile strength, more tractability and processability and also less susceptibility to moisture than polybenzimidazole. 
     
     
       25. Fibers or fibrets as claimed in claim 1 which are comprised of from about 50 weight percent to about 95 weight percent of a polybenzimidazole and from about 50 weight percent to about 5 weight percent of an aromatic polyamide. 
     
     
       26. Fibers or fibrets as claimed in claim 1 which are comprised of at least about 10 weight percent of an aromatic polyamide. 
     
     
       27. Fibers or fibrets as claimed in claim 1 in which the fibers or fibrets are comprised of a major amount of an aromatic polyamide and the polybenzimidazole is present in the fibers or fibrets in a minor amount sufficient to yield fibers or fibrets with increased thermal stability compared to that of the aromatic polyamide, aromatic polyamide-hydrazide or aromatic polyamide containing heterocyclic linkages. 
     
     
       28. Fibers or fibrets as claimed in claim 1 which are comprised of from about 50 weight percent to about 95 weight percent of an aromatic polyamide and from about 50 weight percent to about 5 weight percent of a polybenzimidazole. 
     
     
       29. Fibers or fibrets as claimed in claim 1 which are comprised of at least about 20 weight percent of a polybenzimidazole.

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